Process valves are used in the chemical, pharmaceutical, food and other industries to control or regulate fluid flow. It is desirable to monitor the operational state of a valve, such as whether the valve is opened, partially opened or closed, to ensure that a particular process or activity is actually being performed. One method for monitoring the operational state of a valve is through the use of a valve position sensor such as a limit switch.
Many industries utilize valve islands or manifolds that include a group of valves, such as pneumatic valves, that are mounted on a common base. Such islands typically include an electrical connection and a pneumatic connection for providing electricity and supply air in order to operate the valves in the valve island. An advantage of a valve island is that the island may be expanded by incrementally adding valve stations as needed for a particular process or facility. However, a limit switch is not used in many single valve and valve island configurations for various reasons. A reason is the relatively high cost associated with installation and maintenance of the limit switches. For example, it may be difficult to install electrical wiring for a limit switch that is remotely located in a facility. As a result, it is difficult to remotely monitor the operational state of the valves in the valve island.